For many new mothers returning to work, one accessory is essential: the breast pump.

But the pump, used to express milk so a working woman's eight-or-more-hour separation from her baby need not stop her from breast-feeding, has a limitation: It's helpful only if there's a conducive place to use it.

Washington area women have hooked up electric or manual versions in parked cars, restrooms, a telephone booth and the basement storage room of the National Zoo visitors center, where a box of panda costumes doubled this spring as a table on which one woman set her pump, bottles and other equipment.

Not perhaps what the D.C. Council had in mind when it passed a law in December requiring employers to provide female workers a private, clean space, outside a restroom, to express milk. The Child's Right to Nurse Act also gives a woman the right to breast-feed, covered or not, in any place, public or private, where she has a right to be.

Complying with the law has proved to be a challenge for some local employers, especially those with limited space. Many voice support for the law but say they need time to adjust their facilities or operations. (Women who feel their employer is not following the law can file a complaint with the D.C. Office of Human Rights.)

The law grew out of a national movement aimed at encouraging women to give their children breast milk until age 1, as medical experts recommend. A breast-fed infant is 21 percent less likely to die in the first year than one who is not breast-fed, according to the American Academy of Pediatrics (AAP), and breast milk helps protect babies against a long list of infectious diseases. Some studies suggest it decreases their chances later in life of problems such as diabetes, asthma and cancer. It also appears to improve cognitive development, according to a study published this month in the Archives of General Psychiatry.

For moms, benefits include a lower risk of breast and ovarian cancer as well as protection against weight gain.

But pumping at work can pose so many challenges, including time, space, storage and refrigeration, that some women simply give up.

Unsuitable conditions "have been a major problem," said Ruth Lawrence, a physician who chairs the executive committee of the AAP's breast-feeding section.

Laura Viehmann, a physician who is the breast-feeding coordinator for AAP's Rhode Island chapter, agreed. "If you don't have a private office, this can be a huge thing to negotiate. It's well-documented that there are decreased rates of breast-feeding among working moms. Employment is the biggest obstacle to gains in breast-feeding rates."

A Little Privacy

The new District law joins protections in Virginia and Maryland for nursing moms. Virginia exempts breast-feeding women from indecency laws and allows women to breast-feed on state property but doesn't address the use of breast pumps. In Maryland, a woman may breast-feed her infant in any public or private place, but again the law does not mention pumping. Under federal law, any woman who has a right to be on federal property has a right to breast-feed on that property; there's no word on pumping.

Legal protections for women pumping milk are needed, say breast-feeding advocates, because any disruption in expressing milk could sink a woman's chances of being able to produce enough for her child. If she doesn't have a chance to pump, her supply dwindles.